Chromatography Forum

Hi,

I'm having some repeatability/reproducibility issues that I think it might be due to the tune page open while a run my method for 6 pesticides (6 MRM functions - 2 transitions).
Do you know if I need to create a tune file with cone ramp gradient and collision ramp gradient for the compounds of interest or just close the tune page while running the samples/stds (already done that, not big difference!)?

Regards

Hello Virolarufula,

What instrument is it?

I can think of a few causes, none being related to the tune page being open.

Hi,

I'm using Waters 2695 Alliance and Quattro premier XE. I had the Waters enginner around this week, a quick check on the LC and MS, everything was fine. We thought on the injection volume, did a "weight vial" test and everything was fine (average pick up = 48.5 uL, injection volume = 50uL).

Thanks

Hi
In Quattro Micro, Tune page should be open always.check to see if you've any active ramp in voltage or not?

Hi dr_bahram1977,

I tried both ways, with cone ramp voltage and without, but still the same problem. Yesterday, i try to analyse only one pesticide, using the MS File and MS tune file, still the same problem. It cannot be, injection volume, since I've done the test and even evalutate the final volume after 6 injections.

Regards,

What pesticides are giving you such problems?

Are your dwell times giving you a sufficient number of points across your analyte peaks?

Hi all,

I found the problem, apparently I had a leak on the ESI probe. Just replaced the cappillary, tested for leaks.....and sorted out the problem!

Thanks,